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([140.174.219.137]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cb8d100c18sm815115485a.38.2026.02.23.13.51.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Feb 2026 13:51:15 -0800 (PST) From: Emil Tsalapatis To: bpf@vger.kernel.org Cc: andrii@kernel.org, ast@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, martin.lau@kernel.org, memxor@gmail.com, song@kernel.org, yonghong.song@linux.dev, Emil Tsalapatis Subject: [PATCH bpf-next v3 0/2] bpf: Allow void return type for global subprogs Date: Mon, 23 Feb 2026 16:50:44 -0500 Message-ID: <20260223215046.1706110-1-emil@etsalapatis.com> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Global subprogs are currently not allowed to return void. Adjust verifier logic to allow global functions with a void return type. Exception callbacks are excluded from this change, and still require a scalar return type. Also adjust existing selftests that were ensuring that global subprogs with void return types fail to verify. These tests should now load successfully. v2 -> v3 (https://lore.kernel.org/bpf/20260210183257.217285-1-emil@etsalapatis.com/) - Allow freplace for global programs that return void and add selftests (Kumar) v1 -> v2 (https://lore.kernel.org/bpf/20260127231414.359283-1-emil@etsalapatis.com/) - Only mark R0 as valid for non-void global functions (AI) - Rename subprog_is_void to subprog_returns_void (Kumar) - Add test that R0 is invalid after calling a void global (Alexei) - Add check to ensure exception callbacks do not return void and associated selftest Cc: Kumar Kartikeya Dwivedi Emil Tsalapatis (2): bpf: Allow void global functions in the verifier selftests: bpf: Add tests for void global subprogs kernel/bpf/btf.c | 7 ++- kernel/bpf/verifier.c | 59 +++++++++++++++++-- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 24 ++++++++ .../bpf/prog_tests/test_global_funcs.c | 2 + .../selftests/bpf/progs/exceptions_fail.c | 19 +++++- .../bpf/progs/freplace_int_with_void.c | 14 +++++ .../selftests/bpf/progs/freplace_void.c | 14 +++++ .../selftests/bpf/progs/test_global_func18.c | 23 ++++++++ .../selftests/bpf/progs/test_global_func7.c | 2 +- 9 files changed, 151 insertions(+), 13 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/freplace_int_with_void.c create mode 100644 tools/testing/selftests/bpf/progs/freplace_void.c create mode 100644 tools/testing/selftests/bpf/progs/test_global_func18.c -- 2.49.0